No argument use_mp in kmeans init or fit

[HendrikHuel]

Without openmp the libary throws a warning to set use_mp = True. However, for KMeans use_mp is no valid argument during initialization of the model or during the fitting procedure. It is only possible to omit the warning by altering the default value of use_mp directly in the distance_matrix_fast/distance_matrix functions in the dtw module.

Solution Proporsal: Enable an option to parse use_mp during the call of KMeans().fit().